1/*
2 * RDC321x watchdog driver
3 *
4 * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
5 *
6 * This driver is highly inspired from the cpu5_wdt driver
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 *
22 */
23
24#include <linux/module.h>
25#include <linux/moduleparam.h>
26#include <linux/types.h>
27#include <linux/errno.h>
28#include <linux/miscdevice.h>
29#include <linux/fs.h>
30#include <linux/ioport.h>
31#include <linux/timer.h>
32#include <linux/completion.h>
33#include <linux/jiffies.h>
34#include <linux/platform_device.h>
35#include <linux/watchdog.h>
36#include <linux/io.h>
37#include <linux/uaccess.h>
38#include <linux/mfd/rdc321x.h>
39
40#define RDC_WDT_MASK	0x80000000 /* Mask */
41#define RDC_WDT_EN	0x00800000 /* Enable bit */
42#define RDC_WDT_WTI	0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
43#define RDC_WDT_RST	0x00100000 /* Reset bit */
44#define RDC_WDT_WIF	0x00040000 /* WDT IRQ Flag */
45#define RDC_WDT_IRT	0x00000100 /* IRQ Routing table */
46#define RDC_WDT_CNT	0x00000001 /* WDT count */
47
48#define RDC_CLS_TMR	0x80003844 /* Clear timer */
49
50#define RDC_WDT_INTERVAL	(HZ/10+1)
51
52static int ticks = 1000;
53
54/* some device data */
55
56static struct {
57	struct completion stop;
58	int running;
59	struct timer_list timer;
60	int queue;
61	int default_ticks;
62	unsigned long inuse;
63	spinlock_t lock;
64	struct pci_dev *sb_pdev;
65	int base_reg;
66} rdc321x_wdt_device;
67
68/* generic helper functions */
69
70static void rdc321x_wdt_trigger(unsigned long unused)
71{
72	unsigned long flags;
73	u32 val;
74
75	if (rdc321x_wdt_device.running)
76		ticks--;
77
78	/* keep watchdog alive */
79	spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
80	pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
81					rdc321x_wdt_device.base_reg, &val);
82	val |= RDC_WDT_EN;
83	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
84					rdc321x_wdt_device.base_reg, val);
85	spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
86
87	/* requeue?? */
88	if (rdc321x_wdt_device.queue && ticks)
89		mod_timer(&rdc321x_wdt_device.timer,
90				jiffies + RDC_WDT_INTERVAL);
91	else {
92		/* ticks doesn't matter anyway */
93		complete(&rdc321x_wdt_device.stop);
94	}
95
96}
97
98static void rdc321x_wdt_reset(void)
99{
100	ticks = rdc321x_wdt_device.default_ticks;
101}
102
103static void rdc321x_wdt_start(void)
104{
105	unsigned long flags;
106
107	if (!rdc321x_wdt_device.queue) {
108		rdc321x_wdt_device.queue = 1;
109
110		/* Clear the timer */
111		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
112		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
113				rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
114
115		/* Enable watchdog and set the timeout to 81.92 us */
116		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
117					rdc321x_wdt_device.base_reg,
118					RDC_WDT_EN | RDC_WDT_CNT);
119		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
120
121		mod_timer(&rdc321x_wdt_device.timer,
122				jiffies + RDC_WDT_INTERVAL);
123	}
124
125	/* if process dies, counter is not decremented */
126	rdc321x_wdt_device.running++;
127}
128
129static int rdc321x_wdt_stop(void)
130{
131	if (rdc321x_wdt_device.running)
132		rdc321x_wdt_device.running = 0;
133
134	ticks = rdc321x_wdt_device.default_ticks;
135
136	return -EIO;
137}
138
139/* filesystem operations */
140static int rdc321x_wdt_open(struct inode *inode, struct file *file)
141{
142	if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
143		return -EBUSY;
144
145	return nonseekable_open(inode, file);
146}
147
148static int rdc321x_wdt_release(struct inode *inode, struct file *file)
149{
150	clear_bit(0, &rdc321x_wdt_device.inuse);
151	return 0;
152}
153
154static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
155				unsigned long arg)
156{
157	void __user *argp = (void __user *)arg;
158	u32 value;
159	static const struct watchdog_info ident = {
160		.options = WDIOF_CARDRESET,
161		.identity = "RDC321x WDT",
162	};
163	unsigned long flags;
164
165	switch (cmd) {
166	case WDIOC_KEEPALIVE:
167		rdc321x_wdt_reset();
168		break;
169	case WDIOC_GETSTATUS:
170		/* Read the value from the DATA register */
171		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
172		pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
173					rdc321x_wdt_device.base_reg, &value);
174		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
175		if (copy_to_user(argp, &value, sizeof(u32)))
176			return -EFAULT;
177		break;
178	case WDIOC_GETSUPPORT:
179		if (copy_to_user(argp, &ident, sizeof(ident)))
180			return -EFAULT;
181		break;
182	case WDIOC_SETOPTIONS:
183		if (copy_from_user(&value, argp, sizeof(int)))
184			return -EFAULT;
185		switch (value) {
186		case WDIOS_ENABLECARD:
187			rdc321x_wdt_start();
188			break;
189		case WDIOS_DISABLECARD:
190			return rdc321x_wdt_stop();
191		default:
192			return -EINVAL;
193		}
194		break;
195	default:
196		return -ENOTTY;
197	}
198	return 0;
199}
200
201static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
202				size_t count, loff_t *ppos)
203{
204	if (!count)
205		return -EIO;
206
207	rdc321x_wdt_reset();
208
209	return count;
210}
211
212static const struct file_operations rdc321x_wdt_fops = {
213	.owner		= THIS_MODULE,
214	.llseek		= no_llseek,
215	.unlocked_ioctl	= rdc321x_wdt_ioctl,
216	.open		= rdc321x_wdt_open,
217	.write		= rdc321x_wdt_write,
218	.release	= rdc321x_wdt_release,
219};
220
221static struct miscdevice rdc321x_wdt_misc = {
222	.minor	= WATCHDOG_MINOR,
223	.name	= "watchdog",
224	.fops	= &rdc321x_wdt_fops,
225};
226
227static int rdc321x_wdt_probe(struct platform_device *pdev)
228{
229	int err;
230	struct resource *r;
231	struct rdc321x_wdt_pdata *pdata;
232
233	pdata = dev_get_platdata(&pdev->dev);
234	if (!pdata) {
235		dev_err(&pdev->dev, "no platform data supplied\n");
236		return -ENODEV;
237	}
238
239	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
240	if (!r) {
241		dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
242		return -ENODEV;
243	}
244
245	rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
246	rdc321x_wdt_device.base_reg = r->start;
247
248	err = misc_register(&rdc321x_wdt_misc);
249	if (err < 0) {
250		dev_err(&pdev->dev, "misc_register failed\n");
251		return err;
252	}
253
254	spin_lock_init(&rdc321x_wdt_device.lock);
255
256	/* Reset the watchdog */
257	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
258				rdc321x_wdt_device.base_reg, RDC_WDT_RST);
259
260	init_completion(&rdc321x_wdt_device.stop);
261	rdc321x_wdt_device.queue = 0;
262
263	clear_bit(0, &rdc321x_wdt_device.inuse);
264
265	setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
266
267	rdc321x_wdt_device.default_ticks = ticks;
268
269	dev_info(&pdev->dev, "watchdog init success\n");
270
271	return 0;
272}
273
274static int rdc321x_wdt_remove(struct platform_device *pdev)
275{
276	if (rdc321x_wdt_device.queue) {
277		rdc321x_wdt_device.queue = 0;
278		wait_for_completion(&rdc321x_wdt_device.stop);
279	}
280
281	misc_deregister(&rdc321x_wdt_misc);
282
283	return 0;
284}
285
286static struct platform_driver rdc321x_wdt_driver = {
287	.probe = rdc321x_wdt_probe,
288	.remove = rdc321x_wdt_remove,
289	.driver = {
290		.name = "rdc321x-wdt",
291	},
292};
293
294module_platform_driver(rdc321x_wdt_driver);
295
296MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
297MODULE_DESCRIPTION("RDC321x watchdog driver");
298MODULE_LICENSE("GPL");
299